From: Greg Smith <gsmith@gregsmith.com>
To: pgsql-performance@postgresql.org
Subject: Re: Best OS for Postgres 8.2
Date: Tue, 8 May 2007 23:51:51 -0400 (EDT)
Message-ID: <Pine.GSO.4.64.0705082332480.1773@westnet.com> (raw)
In-Reply-To: <C3E62232E3BCF24CBA20D72BFDCB6BF803EB6A45@MI8NYCMAIL08.Mi8.com>
References: <C3E62232E3BCF24CBA20D72BFDCB6BF803EB6A45@MI8NYCMAIL08.Mi8.com>
On Tue, 8 May 2007, Luke Lonergan wrote:
> From discussions with the developers, the biggest issue is a technical
> one: the Linux VFS layer makes the [ZFS] port difficult.
Difficult on two levels. First you'd have to figure out how to make it
work at all; then you'd have to reshape it into a form that it would be
acceptable to the Linux kernel developers, who haven't seemed real keen on
the idea so far.
The standard article I'm you've already seen this week on this topic is
Jeff Bonwick's at
http://blogs.sun.com/bonwick/entry/rampant_layering_violation
What really bugged me was his earlier article linked to there where he
talks about how ZFS eliminates the need for hardware RAID controllers:
http://blogs.sun.com/bonwick/entry/raid_z
While there may be merit to that idea for some applications, like
situations where you have a pig of a RAID5 volume, that's just hype for
database writes. "We issue the SYNCHRONIZE CACHE command to the disks
after pushing all data in a transaction group"--see, that would be the
part the hardware controller is needed to accelerate. If you really care
about whether your data hit disk, there is no way to break the RPM barrier
without hardware support. The fact that he misunderstands such a
fundamental point makes me wonder what other gigantic mistakes might be
buried in his analysis.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: gsmith@gregsmith.com
Subject: Re: Best OS for Postgres 8.2
In-Reply-To: <Pine.GSO.4.64.0705082332480.1773@westnet.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox